Publications by Year: 2017

We present an overview of imaging and intervention of the extensor mechanism of the knee. Particular focus is placed on the evaluation of patellofemoral tracking disorders, patellar and quadriceps tendinosis and tears, patellar fracture, lateral patellar condyle patellar friction syndrome, and prepatellar bursitis. Anatomical and biomechanical factors contributing to these disorders are considered. Imaging evaluation is presented in a clinical context, and therapeutic options for these disorders are discussed. Image-guided therapy options for symptomatic patellar tendinosis are also described and illustrated.

Bone fracture is a very common body injury. The healing process is physiologically complex, involving both biological and mechanical aspects. Following a fracture, cell migration, cell/tissue differentiation, tissue synthesis, and cytokine and growth factor release occur, regulated by the mechanical environment. Over the past decade, bone healing simulation and modeling has been employed to understand its details and mechanisms, to investigate specific clinical questions, and to design healing strategies. The goal of this effort is to review the history and the most recent work in bone healing simulations with an emphasis on both biological and mechanical properties. Therefore, we provide a brief review of the biology of bone fracture repair, followed by an outline of the key growth factors and mechanical factors influencing it. We then compare different methodologies of bone healing simulation, including conceptual modeling (qualitative modeling of bone healing to understand the general mechanisms), biological modeling (considering only the biological factors and processes), and mechanobiological modeling (considering both biological aspects and mechanical environment). Finally we evaluate different components and clinical applications of bone healing simulation such as mechanical stimuli, phases of bone healing, and angiogenesis.

PURPOSE: Over 50,000 power saw-related injuries occur annually in the United States. Numerous safety measures have been implemented to protect the users of these tools. This study was designed to determine which interventions, if any, have had a positive impact on the safety of the consumer or laborer.

METHODS: We queried the National Electronic Injury Surveillance System database for hand and upper-extremity injuries attributed to power saws from 1997 to 2014. Demographic information including age, sex, date of injury, device, location, body part involved, diagnosis, and disposition was recorded. We performed statistical analysis using interrupted time series analysis to evaluate the incidence of injury with respect to specific safety guidelines as well as temporal trends including patients' age.

RESULTS: An 18% increase in power saw-related injuries was noted from 1997 (44,877) to 2005 (75,037). From 2006 to 2015 an annual decrease of 5.8% was observed. This was correlated with regulations for power saw use by the Consumer Safety Product Commission (CPSC) and Underwriters Laboratories. Mean age of injured patients increased from 48.8 to 52.9 years whereas the proportion of subjects aged less than 50 years decreased from 52.8% to 41.9%. These trends were most pronounced after the 2006 CPSC regulations.

CONCLUSIONS: The incidence of power saw injuries increased from 1997 to 2005, with a subsequent decrease from 2006 to 2015. The guidelines for safer operation and improvements in equipment, mandated by the CPSC and Underwriters Laboratories, appeared to have been successful in precipitating a decrease in the incidence of power saw injuries to the upper extremity, particularly in the younger population.

CLINICAL RELEVANCE: The publication of safety regulations has been noted to have an association with a decreased incidence in power saw injuries. Based on this, clinicians should take an active role in their practice as well as in their professional societies to educate and counsel patients to prevent further injury.

Adhesive shoulder capsulitis, or arthrofibrosis, describes a pathological process in which the body forms excessive scar tissue or adhesions across the glenohumeral joint, leading to pain, stiffness and dysfunction. It is a debilitating condition that can occur spontaneously (primary or idiopathic adhesive capsulitis) or following shoulder surgery or trauma (secondary adhesive capsulitis). Here, we review the pathophysiology of adhesive shoulder capsulitis, highlighting its clinical presentation, natural history, risk factors, pathoanatomy and pathogenesis. Both current non-operative and operative treatments for adhesive capsulitis are described, and evidence-based studies are presented in support for or against each corresponding treatment. Finally, the review also provides an update on the gene expression profile of adhesive capsulitis and how this new understanding can help facilitate development of novel pharmacological therapies.

UNLABELLED: BACKGROUND AND OBJECTIVES Wide margin resection of a soft tissue sarcoma (STS) may require extensive removal of quadriceps muscle with or without the knee extensor mechanism. The objective of this study is to present present the use of a combined functional muscle transfer and soft tissue coverage through the use of chimeric anterolateral thigh flaps.

METHODS: Patients were retrospectively reviewed who underwent deep STS resection of the anterior compartment of the thigh with functional reconstruction of knee extension using a contralateral free anterolateral thigh (ALT) flap.

RESULTS: Three patients with an average age 53.6 years (range: 33-66) were included. Average follow-up was 82 weeks (76-92 months). Full active extension was regained in 66% of patients with all patients regaining active extensor capabilities beyond 100°. The mean Knee Society Score was 83.3 (range; 76-92) and Musculoskeletal Tumor Society Score 21.6 (range; 19-21). Isometric knee extensor strength exceeded 4+/5 in all patients.

CONCLUSION: Following soft tissue sarcoma resections of the lower extremity, chimeric anterolateral thigh flaps for restoration of knee extension can provide significant improvements in the potential for ambulation and regaining quadriceps function.

The objective of this study was to examine the risk to the sciatic nerve and femoral artery during open passage of cerclage wires and to evaluate the safest techniques. After a standard lateral approach, cerclage passes along the femur were made in cadaveric specimens. Distance to the sciatic nerve and femoral artery was recorded. Careful technique resulted in an increase in distance to the sciatic nerve and femoral artery. There was an increase in the distance to the femoral artery with passes in an anterior to posterior direction. There was decreased distance to structures proximally and distally. There was a trend toward increased safety with smaller passers. Open cerclage wiring of the femur is safest if proper technique is used, care is taken at the proximal and distal ends of the femur, passes are made in an anterior to posterior direction, and the smallest cerclage passer that can be passed is utilized.

OBJECTIVES: To determine whether time from injury to fixation of diaphyseal humeral fractures and nonunions is associated with the risk of iatrogenic radial nerve palsy.

DESIGN: Retrospective review.

SETTING: Two Level 1 trauma centers.

PATIENTS/PARTICIPANTS: Between 2001 and 2015, 325 patients who had documented intact radial nerve function preoperatively were treated with fixation of a humerus fracture or humerus nonunion.

INTERVENTION: Open reduction and internal fixation.

MAIN OUTCOME MEASUREMENTS: Development of an iatrogenic radial nerve injury. Those with an injury were followed to either resolution of the nerve palsy or definitive treatment.

RESULTS: The risk of iatrogenic radial nerve palsy was 7.7% (25/325). Time to surgery was not significantly associated with iatrogenic radial nerve palsy. In a multiple variable analysis, when comparing patients treated within 4 weeks to those treated 4-8 weeks (P = 0.41), 8-12 weeks (P = 0.94), and over 12 weeks (0.20), there were no significant associations. Independent risk factors for iatrogenic radial nerve palsy included distal location of fracture (P = 0.04, odds ratio 3.71) and previous fixation (P = 0.03, odds ratio 3.80). Of the 25 iatrogenic nerve injuries, 22 recovered fully with expectant management, 1 was lost to follow-up, and 2 required either nerve graft or tendon transfers.

CONCLUSIONS: Time from injury to surgery does not seem to be a risk factor for developing an iatrogenic radial nerve palsy when treating diaphyseal humerus fractures. Patients with distal fractures, and those with previous fracture implants, are at increased risk of iatrogenic radial nerve palsy.

LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND: A microRNA (miRNA) collection on the imprinted 14q32 MEG3 region has been associated with outcome in osteosarcoma. We assessed the clinical utility of this miRNA set and their association with methylation status.

METHODS: We integrated coding and non-coding RNA data from three independent annotated clinical osteosarcoma cohorts (n = 65, n = 27, and n = 25) and miRNA and methylation data from one in vitro (19 cell lines) and one clinical (NCI Therapeutically Applicable Research to Generate Effective Treatments (TARGET) osteosarcoma dataset, n = 80) dataset. We used time-dependent receiver operating characteristic (tdROC) analysis to evaluate the clinical value of candidate miRNA profiles and machine learning approaches to compare the coding and non-coding transcriptional programs of high- and low-risk osteosarcoma tumors and high- versus low-aggressiveness cell lines. In the cell line and TARGET datasets, we also studied the methylation patterns of the MEG3 imprinting control region on 14q32 and their association with miRNA expression and tumor aggressiveness.

RESULTS: In the tdROC analysis, miRNA sets on 14q32 showed strong discriminatory power for recurrence and survival in the three clinical datasets. High- or low-risk tumor classification was robust to using different microRNA sets or classification methods. Machine learning approaches showed that genome-wide miRNA profiles and miRNA regulatory networks were quite different between the two outcome groups and mRNA profiles categorized the samples in a manner concordant with the miRNAs, suggesting potential molecular subtypes. Further, miRNA expression patterns were reproducible in comparing high-aggressiveness versus low-aggressiveness cell lines. Methylation patterns in the MEG3 differentially methylated region (DMR) also distinguished high-aggressiveness from low-aggressiveness cell lines and were associated with expression of several 14q32 miRNAs in both the cell lines and the large TARGET clinical dataset. Within the limits of available CpG array coverage, we observed a potential methylation-sensitive regulation of the non-coding RNA cluster by CTCF, a known enhancer-blocking factor.

CONCLUSIONS: Loss of imprinting/methylation changes in the 14q32 non-coding region defines reproducible previously unrecognized osteosarcoma subtypes with distinct transcriptional programs and biologic and clinical behavior. Future studies will define the precise relationship between 14q32 imprinting, non-coding RNA expression, genomic enhancer binding, and tumor aggressiveness, with possible therapeutic implications for both early- and advanced-stage patients.

AIM: To describe an approach to anterior cruciate ligament (ACL) reconstruction using autologous hamstring by drilling via the anteromedial portal in the presence of an intramedullary (IM) femoral nail.

METHODS: Once preoperative imagining has characterized the proposed location of the femoral tunnel preparations are made to remove all of the hardware (locking bolts and IM nail). A diagnostic arthroscopy is performed in the usual fashion addressing all intra-articular pathology. The ACL remnant and lateral wall soft tissues are removed from the intercondylar, to provide adequate visualization of the ACL footprint. Femoral tunnel placement is performed using a transportal ACL guide with desired offset and the knee flexed to 2.09 rad. The Beath pin is placed through the guide starting at the ACL's anatomic footprint using arthroscopic visualization and/or fluoroscopic guidance. If resistance is met while placing the Beath pin, the arthroscopy should be discontinued and the obstructing hardware should be removed under fluoroscopic guidance. When the Beath pin is successfully placed through the lateral femur, it is overdrilled with a 4.5 mm Endobutton drill. If the Endobutton drill is obstructed, the obstructing hardware should be removed under fluoroscopic guidance. In this case, the obstruction is more likely during Endobutton drilling due to its larger diameter and increased rigidity compared to the Beath pin. The femoral tunnel is then drilled using a best approximation of the graft's outer diameter. We recommend at least 7 mm diameter to minimize the risk of graft failure. Autologous hamstring grafts are generally between 6.8 and 8.6 mm in diameter. After reaming, the knee is flexed to 1.57 rad, the arthroscope placed through the anteromedial portal to confirm the femoral tunnel position, referencing the posterior wall and lateral cortex. For a quadrupled hamstring graft, the gracilis and semitendinosus tendons are then harvested in the standard fashion. The tendons are whip stitched, quadrupled and shaped to match the diameter of the prepared femoral tunnel. If the diameter of the patient's autologous hamstring graft is insufficient to fill the prepared femoral tunnel, the autograft may be supplemented with an allograft. The remainder of the reconstruction is performed according to surgeon preference.

RESULTS: The presence of retained hardware presents a challenge for surgeons treating patients with knee instability. In cruciate ligament reconstruction, distal femoral and proximal tibial implants hardware may confound tunnel placement, making removal of hardware necessary, unless techniques are adopted to allow for anatomic placement of the graft.

CONCLUSION: This report demonstrates how the femoral tunnel can be created using the anteromedial portal instead of a transtibial approach for reconstruction of the ACL.